Humans have forever been intrigued by the night sky. Stars and other celestial objects have religious, scientific, emotional and mythical importance to peoples of all cultures. Countless books and stories describe specific stars, star groupings and other celestial objects but most people find it difficult to locate a specific object in the sky. Many devices have been created to help, including two and three dimensional planispheres and other such aids.
Optical instruments such as binoculars and telescopes are often mounted on sturdy platforms and equipped with rotational sensors to determine the azimuth and altitude at which the instrument is pointed. Azimuth and altitude are a coordinate system that allows unambiguous determination of a direction from a given point, as described below. A connected computer can use the azimuth and altitude information coordinates, along with current time, date and viewing location to determine the celestial coordinates at which the instrument is pointing, and determines from a database of celestial objects the object at which the instrument is pointed. Information about that object is then retrieved from the database and made known to the user, typically through visual means, such as by producing text on a computer screen.
Such optical instruments are useful not only to identify the object at which the instrument is pointed, but also to locate an object of interest to the viewer. The user specifies the object of interest, for example the star Sirius. If the instrument is equipped with motors, the instrument can be controlled to change its azimuth and altitude until it matches the current location of Sirius. Alternatively, the instrument can provide directional cues to the user so he can manually adjust the instrument until it points at the current location of Sirius. Such optical instruments are widely available and well known to those skilled in the art of telescopes or astronomy. These instruments perform well but are relatively heavy, require alignment and a solid physical mounting.
Some optical instrument designs reduce these limitations by replacing the rotational sensors with sensors of Earth's gravitational pull and magnetic field, thereby eliminating the needs for alignment and the solid physical mounting, thus allowing handheld operation. These designs still require sighting of the object of interest through a viewing axis which can obstruct the user's view of the object and require uncomfortable positioning of the viewing device. Further, requiring that the observation take place along a viewing axis makes such devices unusable by more than one person at a time.
Embodiments of the invention address these and other limitations in the prior art.